Eicosatrienoic acid (ETrA) is the n-9 homologue of arachidonic acid and normally found in tissues at very low levels. ETrA can be incorporated into cell membranes and may compete for access to eicosanoid forming enzymes. In the present study, incorporation of dietary ETrA into leukocytes was measured in rats. The influence of dietary linoleic acid was also checked. ETrA was efficiently incorporated into peritoneal exudate cells (PEG)up to 10% of total fatty acids in phospholipids in PEC without saturation phenomenon. The efficiency of accumulation was reduced significantly by increasing dietaly LA levels above essential requirements. ETrA accumulation correlated with reduced LTB4 synthesis by PEG following stimulation in vitro. This effect was attributable to inhibition of LTA4 hydrolase. Thus, dietaly ETrA can modulate inflammatory eicosanoid synthesis. The findings juslify further studies into the biochemical and anti- inflammatory effects of dietary ETrA.